A hydrogen-occlusion electrode primarily composed of a hydrogen-occlusion alloy capable of occluding and releasing hydrogen has previously been proposed for use as a negative electrode of a sealed-type alkaline storage battery in which hydrogen is used as the active material for the negative electrode. To manufacture this type of hydrogen-occlusion electrode, a polytetrafluoroethylene (PTFE) powder or a polyethylene (PE) powder, which serves as a bonding material, is mixed with a hydrogen-occlusion alloy powder which is the main component of the electrode. The mixture is heated sufficiently to bond the alloy powder particles together. Alternatively, an unsintered PTFE powder is mixed with a hydrogen-occlusion alloy powder and formed into fibers. During the formation of these fibers, particles of the alloy powder are bonded to one another in order to prevent the alloy powder particles from separating from the formed fibers. In this case, it has been the general practice to add an electroconductive material, such as a nickel (Ni) powder, to the mixture to increase the conductivity of the electrode. Further, a thickener, such as carboxymethylcellulose (CMC) is added to the mixture to make the mixture a slurry. The resultant slurry mixture can then be applied to a porous or perforated electroconductive substrate, dried and pressed to a predetermined thickness to form an electrode plate body. This body is thereafter heat-treated in a vacuum or inert gas atmosphere to produce a hydrogen-occlusion electrode.
With the types of hydrogen-occlusion electrodes manufactured by the above-identified conventional manufacturing methods, however, it has been found that as the electrode is repeatedly subjected to charge-discharge operations in an alkaline electrolyte while in use as a negative electrode of a storage battery, pulverization of the hydrogen-occlusion alloy powder contained in the electrode takes place resulting in finer-sized particles of the hydrogen alloy powder which separate from the electrode. This results in not only a capacity decrease in the battery, but also a sharp deterioration in both the mechanical strength and electroconductivity of the electrode, thereby making it difficult to maintain a high capacity rate for a long time.
Further, it has been the general practice with convention hydrogen-occlusion electrodes containing a thickener, that the thickener be present in an amount of about 1 wt. % based on the weight of the hydrogen-occlusion alloy of the electrode. However, this has been found to cause the surfaces of the alloy particles to become covered with the thickener resulting in lower electrode activity, a comparatively short life in terms of charge-discharge cycles, and a higher internal pressure for the sealed-type storage battery containing the electrode. It is desired to avoid these disadvantages.